#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int

sbit duan=P2^6;
sbit wei=P2^7;

uchar code table[]={
0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71};

void delay(uint z)
{
 uint x,y;
 for(x=z;x>0;x--)
  for(y=110;y>0;y--);
}

void display(uchar num)
{
 P0=table[num];
 duan=1;
 duan=0;
}

void matrixkeyscan()
{
 uchar temp,key;
 
 P3=0xfe;
 temp=P3;
 temp=temp&0xf0;
 if(temp!=0xf0)  
 {               
  delay(10);  
  temp=P3;  
  temp=temp&0xf0;
  if(temp!=0xf0)
  {
   temp=P3;
   switch(temp)
   {
    case 0xee;
     key=0;
     break;
    case 0xde;
     key=1;
     break;
    case 0xbe;
     key=2;
     break;
    case 0x7e;
     key=3;
     break;
     
   }
   while(temp!=0xf0)
   {
    temp=P3;
    temp=temp&0xf0;
   }    
   display(key);
  } 
 }

 P3=0xfd;
 temp=P3;
 temp=temp&0xf0;
 if(temp!=0xf0)  
 {              
  delay(10);  
  temp=P3;  
  temp=temp&0xf0;
  if(temp!=0xf0)
  {
   temp=P3;
   switch(temp)
   {
    case 0xed;
     key=4;
     break;
    case 0xdd;
     key=5;
     break;
    case 0xbd;
     key=6;
     break;
    case 0x7d;
     key=7;
     break;
     
   }
   while(temp!=0xf0)
   {
    temp=P3;
    temp=temp&0xf0;
   }    
   display(key);
  } 
 }

 P3=0xfb;
 temp=P3;
 temp=temp&0xf0;
 if(temp!=0xf0)  
 {              
  delay(10);  
  temp=P3;  
  temp=temp&0xf0;
  if(temp!=0xf0)
  {
   temp=P3;
   switch(temp)
   {
    case 0xeb;
     key=8;
     break;
    case 0xdb;
     key=9;
     break;
    case 0xbb;
     key=10;
     break;
    case 0x7b;
     key=11;
     break; 
   }
   while(temp!=0xf0)
   {
    temp=P3;
    temp=temp&0xf0;
   }    
   display(key);
  } 
 }

 P3=0xf7;
 temp=P3;
 temp=temp&0xf0;
 if(temp!=0xf0)  
 {               
  delay(10);  
  temp=P3;  
  temp=temp&0xf0;
  if(temp!=0xf0)
  {
   temp=P3;
   switch(temp)
   {
    case 0xe7;
     key=12;
     break;
    case 0xd7;
     key=13;
     break;
    case 0xb7;
     key=14;
     break;
    case 0x77;
     key=15;
     break;
     
   }
   while(temp!=0xf0)
   {
    temp=P3;
    temp=temp&0xf0;
   }    
   display(key);
  } 
 }
}

void main()
{
 P0=0;
 duan=1;
 duan=0;
 P0=0xc0;
 wei=1;
 wei=0;
 while(1)
 {
  matrixkeyscan();
 }
}

已找到問題點，CASE語句后誤用了分號造成。